Summary of the invention
The connect battery of multiple secondary cells as lithium rechargeable battery, voltage rises with the number of secondary cell.Therefore, need to improve element withstand voltage that forms battery protection circuit device, so that element can not damage in the time being applied in above-mentioned voltage.Conventionally, withstand voltage if semiconductor element improves, the size of element, element separated region can become large.
Thereby, the battery protection circuit device of multiple secondary cells of connecting, not only because the circuit that increases of battery number increases, and the size that forms each semiconductor element of this circuit also becomes greatly, thereby the overall dimensions of protective circuit device is become greatly.
So far,, though there are many patent applications of battery protecting circuits about the multiple secondary cells of series connection, do clearly almost not having of narration for semiconductor element withstand voltage that forms this circuit.For example, in circuit shown in Fig. 3 of patent documentation 1, where the current potential of not describing trap is located at, and what degree the withstand voltage of this element is.Can be inferred by accompanying drawing, the NOR gate of G2, G3 is the same, and the comparison circuit of COMP1~4 is located between the Power supply and grounding of whole protective circuit thus.That is, be likely applied in all voltage of series connection, the withstand voltage needs of element become all voltage deals of series connection.So example, compared with the occasion that is 1, needs 2 times withstand voltage with described secondary cell, and therefore withstand voltage in order to meet this, it is large that component size can become.
In this example, secondary cell is 2, therefore terminates in 2 times, if 10 of series connection need 10 times withstand voltage.That is, the number of the secondary cell of series connection is more, and required is withstand voltage just larger, and it is larger that component size becomes.Thereby the protective circuit device of battery becomes larger.
In addition, semiconductor element conventionally because of manufacture time process deviation, its characteristic has deviation.Therefore, is conventionally furnished with correction (trimming) circuit.This deviation generally increases with withstand voltage rising, therefore withstand voltage higher, needs the scope of correction wider, and correction circuit increases, and it is large that the area of battery protection circuit device becomes.
And if the deviation of element characteristic is large, detection voltage when variations in temperature has larger biasing.This causes the precision that detects voltage to reduce.So, the deviation of element characteristic is large, and the precision of various characteristics just reduces.If be equipped with the circuit of proofreading and correct these, it is large that the area of protective circuit device just becomes.
As more than, it is large that the area of the battery protection circuit device of multiple secondary cells of connecting becomes.For semiconductor device, the increase of area directly increases and is connected with cost.Thereby existence can not provide the problem of battery protection circuit device at a low price.
In order to solve above-mentioned problem, battery protection circuit device of the present invention adopts following means.
A kind of battery protection circuit device; multiple secondary cells of making charging and discharging of having connected; it is characterized in that; detect the voltage of each secondary cell with reference voltage; occur in each reference voltage circuit of this reference voltage, power supply terminal is connected with the positive pole of each detected secondary cell, and earth terminal is connected with the negative pole of each detected secondary cell; form the withstand voltage voltage higher than 1 secondary cell of the element of described reference voltage circuit, and lower than the voltage of all batteries.
A kind of battery protection circuit device; detect the voltage of each secondary cell; and make comparisons with reference voltage; it is characterized in that; survey overcharge condition, the over-discharge state of described secondary cell, the power supply terminal of this each voltage detecting circuit is connected with the positive pole of each detected secondary cell, and earth terminal is connected with the negative pole of each detected secondary cell; form the withstand voltage voltage higher than 1 secondary cell of the element of described voltage detecting circuit, and lower than the voltage of all batteries.
A kind of battery protection circuit device, it is characterized in that, detect the voltage of each secondary cell, and make comparisons with reference voltage, thereby voltage detecting circuit is surveyed the overcharge condition of described secondary cell, over-discharge state, output to level shift circuit input from this voltage detecting circuit, and the output from level shift circuit is input to control circuit, this control circuit is to reduce supply voltage or to heighten earth level, operation voltage band is narrowed, in such circuit forms, described reference voltage circuit, the power supply terminal of voltage detecting circuit and the positive pole of each detected secondary cell, and earth terminal is connected with the negative pole of each detected secondary cell, form described reference voltage circuit, the withstand voltage voltage higher than 1 secondary cell of the element of voltage detecting circuit, and lower than the voltage of all batteries.
A kind of battery protection circuit device; it is characterized in that; at least between the voltage detecting each terminal of terminal that connects each secondary cell; and there is esd protection element between the terminal of the maximum potential of the secondary cell being connected in series and the terminal of potential minimum; the withstand voltage voltage higher than 1 secondary cell of the esd protection element between terminal for the former each voltage detecting; and lower than the voltage of all batteries, the withstand voltage voltage higher than all batteries of the latter's esd protection element.
A kind of battery protection circuit device; it is characterized in that; the power supply terminal of reference voltage circuit, voltage detecting circuit, earth terminal are connected to the two ends of the multiple secondary cells that are connected in series that comprise detected secondary cell, form the withstand voltage voltage lower than all batteries of the element of described circuit.
(invention effect)
According to the present invention, in the battery protecting circuit that is connected in series many secondary cells, necessity of the element of formation reference voltage circuit, voltage detecting circuit, control circuit is withstand voltage can be the voltage of 1 secondary cell deal.In addition,, in the battery protecting circuit of many secondary cells of connecting, necessity of the esd protection element being connected with the terminal of the voltage for detection of secondary cell is withstand voltage can be also the voltage of 1 secondary cell deal.So, even if the number of secondary cell increases, the withstand voltage of necessity also can not increase, and can reduce the size of said elements compared with conventional art.
In addition, if the withstand voltage reduction of element can reduce than withstand voltage high occasion the deviation of element.This is relevant with dwindling of correction circuit.
In addition, the deviation of element diminishes, and the biasing that can the obtain temperature variant detection voltage effect that precision is improved such as yet diminish, does not therefore just need the circuit of this class for proofreading and correct.
As mentioned above, according to the present invention, in the battery protecting circuit that is connected in series many secondary cells, identical also can make withstand voltage and 1 secondary cell deal of the element that forms foregoing circuit time, therefore can reduce battery protection circuit device compared with conventional art., can solve described problem.
Embodiment
According to Fig. 1, the occasion of the battery protection circuit device that is connected in series 4 secondary cells is described.The voltage detecting terminal of the battery protection circuit device being connected with each secondary cell of secondary cell A1~A4 is decided to be to V0~V4.V0 is for subordinate and be made as Vss, and V4 is for higher level and be made as Vdd.In addition, the positive terminal 108 of Vdd and battery is idiostatic, and Vss and negative terminal 109 are idiostatic.
Between each terminal of V0~V1, V1~V2, V2~V3, V3~V4, configuration voltages detects with esd protection element 102, reference voltage circuit 103 and voltage detecting circuit 104 between terminal.In addition, between Vdd~Vss, configure esd protection element 101 between Vdd~Vss.Reduction voltage circuit 107, take Vdd as benchmark, is new earth connection Vss2.Based on reference voltage, detect the voltage of each secondary cell with voltage detecting circuit 104, its result is delivered to level shift circuit 105, level shift circuit is transformed to signal the voltage amplitude of Vdd~Vss2, delivers to control circuit 106.Control circuit 106 is in the voltage range action of Vdd~Vss2.
Fig. 2 illustrates an example of reference voltage circuit 103.So, by being connected in series constant current depletion type N channel transistor 111 and N channel transistor 112, can obtain the reference voltage take earth terminal as benchmark.
The power supply terminal of this circuit is connected to the positive pole of detected secondary cell, and earth terminal is connected to the negative pole of detected secondary cell.As shown in Figure 1, reference voltage circuit 103 is also connected in series to secondary cell, therefore common for detection of the power supply terminal of reference voltage circuit of secondary cell A1 and the earth terminal of the reference voltage circuit for detection of secondary cell A2 of upper level.So, the power supply terminal of subordinate and the earth terminal of upper level are common.
Next, Fig. 3 illustrates an example of the voltage detecting circuit of secondary cell A2.Select A2 without Special Significance at this, understandable just to making to illustrate.This circuit is voltage and the described reference voltage that the resistance R 1, R2, the R3 that configure between comparison V1~V2 are cut apart, and according to the potential difference between V1~V2, the voltage ratio of battery A2 value is large or little, makes to export anti-phase circuit, is generally referred to as comparison circuit.At this, because its effect is referred to as voltage detecting circuit.
This circuit comprises: for p channel transistor 113 that electric current is turned back, make Ibias become the N channel transistor 114 of Gate current potential and accept the N channel transistor 115 of 2 input signals that compare in order to control the electric current that comparison circuit flows.
The positive pole that the power supply terminal of this circuit is connected to detected secondary cell A2 is V2, and the negative pole that earth terminal is connected to detected secondary cell A2 is V1.As shown in Figure 1, voltage detecting circuit 104 is also connected in series to secondary cell, for detection of the power supply terminal of the voltage detecting circuit of secondary cell A2, common with the earth terminal of the voltage detecting circuit of the secondary cell A3 of detection upper level.So, the power supply terminal of subordinate and the earth terminal of upper level are common.
Above, described herein is reference voltage circuit and voltage detecting circuit between V1~V2, but the circuit of Fig. 2 is an example that produces the circuit of reference voltage, and the circuit of Fig. 3 is an example that compares the circuit of the voltage that detects secondary cell with reference voltage, is not limited to this circuit.
Reduction voltage circuit is then described.Shown in Fig. 1, use N-type wafer (Wafer), take N trap as common electric potential, make N trap become the occasion of Vdd current potential.Now, reduction voltage circuit is exported take Vdd as benchmark, the Vss2 level of for example Vss2=Vdd-3V.Control circuit moves in the voltage range of the Vss2~Vdd by this reduction voltage circuit constriction.Although this sentences Vdd is benchmark, also can take Vss as benchmark.
From the output signal of each voltage detecting circuit, because above-mentioned circuit structure becomes different separately amplitude voltages, as being Lo=V0, Hi=V1 between V0~V1; Between V1~V2, be Lo=V1, Hi=V2.Therefore, be input to control circuit 106 after being shaped as the signal with the amplitude voltage between Vss2~Vdd with level shift circuit.
The in the situation that of said structure, for each voltage detecting, the esd protection element 102 between terminal, reference voltage circuit 103, voltage detecting circuit 104, control circuit 106 can be formed by the withstand voltage element with 1 secondary cell deal.In the past the connected occasion of 4 secondary cells, need to have 4 secondary cell deals, that is, and and 4 times of withstand voltage elements.In the occasion of conventional art, if the number of the secondary cell being connected in series increases, the correspondingly required withstand voltage rising of element.By comparison, occasion of the present invention, forms element required withstand voltage of foregoing circuit, no matter be connected in series how many secondary cells, is all the voltage of 1 secondary cell deal.
Thereby, according to the present invention, owing to can the withstand voltage of element that form foregoing circuit being suppressed lowlyer, can reduce component size.Reduce component size, be equivalent to battery protection circuit device overall dimensions little, therefore can reduce the cost., can solve above-mentioned problem.
Constant at this explanation cell voltage, but the required withstand voltage reason that can decline of element.In the occasion of circuit structure in the past, the voltage applying between the drain electrode of set trap and each element in Semiconductor substrate is cell voltage to the maximum.In occasion of the present invention, owing to making the trap potential of the element that forms the circuit between each terminal become the current potential between each terminal, the voltage maximum applying between the drain electrode of trap and each element is also 1 secondary cell deal, replaces, and voltage can be applied between trap and substrate.This occasion packs multiple elements in 1 trap, as long as each trap guarantees the withstand voltage of supply voltage deal, therefore, compared with traditional withstand voltage occasion of guaranteeing supply voltage deal by each element, can dwindle area.
The occasion of lithium rechargeable battery, is often used N-type substrate, describes according to Fig. 4 about this situation.Fig. 4 is the conventional case of the voltage detecting circuit of secondary cell A2.In the occasion of conventional art, because the N trap of formation p channel transistor is identical with substrate polarity, generally make the current potential of the N trap of p channel transistor become Vdd.Therefore, for example, be applied in the situation of voltage maximum of the voltage detecting circuit of the battery of A1 and equate with supply voltage, withstand voltage needs of element are supply voltage deal.
Shown in Fig. 4, the current potential of P trap that forms N raceway groove is taken as to the occasion of Vss, but P trap can electrically separate from N-type substrate, therefore get as shown in Figure 3 V1 and also can.Get the occasion of V1,2 power supply terminals of this voltage detecting circuit become Vdd, and earth terminal becomes V1, and the scope from the output voltage of voltage detecting circuit at Vdd~V1, therefore needs level shift circuit.On the other hand, in the occasion of Fig. 4, the power supply terminal of voltage detecting circuit becomes Vdd, and earth terminal becomes Vss, and the scope from the output voltage of voltage detecting circuit at Vdd~Vss, does not therefore need level shift circuit.
In addition, utilize P type embedding layer or insulating barrier etc., make to form N trap and the substrate separation of p channel transistor, thereby also can realize described circuit structure.In this case, compared with conventional art, need the new region for N trap~N-type substrate is electrically separated, this point can make area increase, and but can obtain the better effect of area reducing.
Resistance R 1~R3 of Fig. 3, in function as Fig. 3 just can, but in fact have deviation because process variations causes element characteristic, become the correction circuit that comprises as shown in Figure 5.This fuse 116 by resistance 117 and configuration in parallel with it forms.If element characteristic has deviation, or on reference voltage, occur deviation, or produce bias voltage between 2 inputs of comparison circuit.Correction circuit has such function: even if there is such deviation, also can, by cutting off or do not cut off fuse 116 and come the ration of division of the voltage that adjusting resistance R1~R3 produces, make overcharge voltage, the overdischarge voltage of battery protection circuit device keep certain.
The deviation that general low withstand voltage element has the element characteristic of the process variations followed is less than high withstand voltage element tendency.The deviation of element characteristic is less, and the scope of the ration of division of resistance that need be corresponding is just narrower, and therefore required resistance and fuse tail off.Thereby according to the present invention, correction circuit also can do little.
Correction circuit in this narration is made up of resistance and fuse, but not limited by this.Correction circuit has various ways, as replaced fuse etc. with memory element, no matter which kind of is, as long as need the ration of division of corresponding resistance to narrow, just can reduce correction circuit, therefore can obtain same effect.
In addition, because the deviation of element characteristic diminishes, obtain not only not needing above-mentioned correction circuit, nor need various correcting circuits, or improve the effect of voltage detecting precision etc.
Esd protection element is then described.As shown in Figure 1, between Vdd~Vss, adding esd protection element 101 between Vdd~Vss.In addition, V0~V4 adds esd protection element 102 between voltage detecting terminal between each.This class esd protection element generally uses the N-type transistor of diode or normally closed (normally off).
Between Vdd~Vss, esd protection element 101 withstand voltage must be more than the voltage of all batteries, but voltage detecting with the withstand voltage of esd protection element 102 between terminal as long as more than 1 secondary cell deal.In addition,, because protecting internal circuit, be necessary to puncture than internal circuit is Zao.The withstand voltage of protection component of explanation refers to herein, is that its opposite direction punctures withstand voltage in the situation with diode formation protection component.
For example; in the time that the voltage of 1 secondary cell is 4V; the withstand voltage of element that forms reference voltage circuit, voltage detecting circuit must be more than 4V, and by the withstand voltage occasion that is made as 6V of element, voltage detecting must be between 4V and 6V with the withstand voltage of esd protection element between terminal.
In the occasion of conventional art; 2 power lines of constant voltage circuit, voltage detecting circuit are not connected to the two ends of detected secondary cell as mentioned above; and one or two is connected to Vdd or Vss; therefore in order to protect internal circuit, be necessary esd protection arrangements of components between the each terminal~Vdd and each terminal~Vss for voltage detecting.Or, be necessary to be configured between each terminal and a side of Vdd or Vss, and between Vdd~Vss.Now, more than the voltage of the withstand voltage secondary cell that need to be between them of esd protection element.Thereby, according to the present invention, can the withstand voltage of esd protection element be suppressed lowlyer, thereby can reduce the size of esd protection element.
Battery protection circuit device, generally, except described circuit, also has the circuit or the input/output terminal that charge or discharge are carried out to conduction and cut-off or detection of excessive current.In addition, be also useful on the circuit of realizing various functions beyond these, but the present invention to these without any feature, description will be omitted.In addition,, although be connected in series 4 secondary cells in Fig. 1, be not limited to this number.No matter be connected in series how many, the present invention also can be suitable for.
Embodiment 1
Be connected in series in the battery protection circuit device of multiple secondary cells, as shown in Figure 1, reference voltage circuit be configured in respectively between the each secondary cell being connected in series, this reference voltage circuit produces reference voltage, in order to detect each secondary cell voltage separately.
According to Fig. 2, describe with regard to an example of this reference voltage circuit.Fig. 2 is the reference voltage circuit for detection of the voltage of battery A2.Other the reference voltage circuit for detection of battery is also identical, and therefore here A2, without particular meaning, is a simple example.As shown in Figure 2, by being connected in series constant current depletion type N channel transistor 111 and N channel transistor 112, can obtain the reference voltage take V1 as benchmark.
The positive pole that the high-voltage side of 2 power lines of this circuit is connected to detected secondary cell A2 is V2, and the negative pole that low voltage side is connected to detected secondary cell A2 is V1.At this, be called as the power line of circuit, adopt said structure, thereby can form reference voltage circuit by the withstand voltage element with 1 secondary cell deal.So, can suppress to form element required withstand voltage of reference voltage circuit, make it lower than conventional art, thereby can reduce area.
Emphasis of the present invention is the two ends that 2 power lines of reference voltage circuit are connected to detected secondary cell, and the mode of reference voltage circuit has multiple except Fig. 2, but there is no purpose for which.Thereby the present invention is not limited to the reference voltage circuit of Fig. 2.In addition, the situation of 4 batteries of connecting has been shown in Fig. 1, and to this quantity also without purpose.Be connected in series exactly several secondary cells, forming required withstand voltage of the element of described reference voltage circuit is also 1 secondary cell deal.
Embodiment 2
Be connected in series in the battery protection circuit device of multiple secondary cells, as shown in Figure 1, voltage detecting circuit be configured in respectively between the each secondary cell being connected in series.This voltage detecting circuit detects each secondary cell voltage separately, and compares with reference voltage and survey overcharge condition, the over-discharge state of described secondary cell.
According to Fig. 3, an example of this voltage detecting circuit is described.Fig. 3 is the voltage detecting circuit for detection of the voltage of battery A2.The voltage detecting circuit of other detection battery too, does not therefore have special purpose to A2 here, is a simple example.
The voltage detecting circuit of Fig. 3 is voltage and the described reference voltage that the resistance R 1, R2, the R3 that configure between comparison V1~V2 are cut apart, and according to the potential difference between V1~V2, the voltage ratio of battery A2 value is large or little, makes to export anti-phase circuit.Identical with the circuit that is commonly referred to as comparison circuit.But be referred to as voltage detecting circuit with its effect here.This circuit comprises p channel transistor 113 for electric current is turned back, makes Ibias become the N channel transistor 114 of Gate current potential and accept two N channel transistors 115 of relatively using input signal in order to control the electric current that comparison circuit flows.The positive pole that the high-voltage side of 2 power lines of this circuit is connected to detected secondary cell A2 is V2, and the negative pole that low voltage side is connected to detected secondary cell A2 is V1.
Comparison circuit carries 2 as shown in Figure 3, and the voltage comparing is also the different voltages of being cut apart by R1~R3.This is because due to different with the detection voltage of surveying for overdischarge for the detection voltage of detection that overcharges.
Because adopting above structure, voltage detecting circuit can be formed by the withstand voltage element of 1 secondary cell deal.So, compared with conventional art, the necessity that can suppress the element that forms this voltage detecting circuit is withstand voltage lower, thereby can reduce area.
Emphasis of the present invention is the two ends that 2 power lines of voltage detecting circuit are connected on to detected secondary cell, and the mode of voltage detecting circuit has multiple except Fig. 3, but its mode is not had to purpose.Thereby the present invention is not limited to the voltage detecting circuit of Fig. 3.And, the situation of 4 batteries of connecting shown in Fig. 1, and this quantity is not had to purpose yet.Be connected in series exactly several secondary cells, form the element of described voltage detecting circuit required withstand voltage be also 1 secondary cell deal.
Embodiment 3
Be connected in series in the battery protection circuit device of multiple secondary cells; as shown in Figure 1; esd protection arrangements of components is used between each terminal of terminal in the voltage detecting that has connected each secondary cell, and between the maximum potential Vdd of the secondary cell being connected in series and potential minimum Vss.
Between the former each terminal, esd protection element 102 is withstand voltage more than the voltage of a secondary cell deal, and between Vdd~Vss of the latter, the withstand voltage of esd protection element 101 need be higher than the voltage of all batteries.In addition, owing to must protecting internal circuit, need to puncture than internal circuit is Zao.This esd protection element generally uses diode or normally closed N-type transistor.Protection component withstand voltage of explanation be that reverse breakdown during with diode formation protection component is withstand voltage herein.
In the occasion of conventional art; 2 power lines of constant voltage circuit, voltage detecting circuit are not connected on the two ends of detected secondary cell as mentioned above; and a side or two sides are connected on Vdd or Vss; therefore in order to protect this circuit from ESD, be necessary esd protection arrangements of components between the each terminal~Vdd and each terminal~Vss for voltage detecting.Or, be necessary to be configured between each terminal and a side of Vdd or Vss, and between Vdd~Vss.Now, more than the voltage of the withstand voltage secondary cell that need be between them of esd protection element.Thereby, according to the present invention, can suppress the withstand voltage of esd protection element, make it lower than conventional art, thereby can reduce the size of element.
At this, just about the esd protection element of terminal of the present invention is narrated.Actual battery protection circuit device also has other terminal, thus also there is above-mentioned esd protection element in addition, but unrelated to the invention, so description thereof is omitted.
Embodiment 4
In example now, the two ends of 1 detected secondary cell have connected power supply terminal and the earth terminal of each circuit, but the occasion of this mode, only at least need from the trap of the number deal of the secondary cell of connecting.According to the voltage of secondary cell and quantity, collect the several batteries that comprised detected secondary cell, connect the mode of power supply terminal and the earth terminal of each circuit at its two ends, favourable aspect area.Now, necessity of the element of forming circuit is withstand voltage becomes the voltage of the number deal of the detected secondary cell collecting, and therefore higher than the occasion of only having 1, but as mentioned above the quantity of the different trap of current potential reduces, and therefore sometimes can reduce entire area.
(symbol description)
Esd protection element between 101 Vdd~Vss
Esd protection element between terminal for 102 voltage detecting
103 reference voltage circuits
104 voltage detecting circuits
105 level shift circuits
106 control circuits
107 reduction voltage circuits
The positive terminal of 108 batteries
The negative terminal of 109 batteries
111 depletion type N channel transistors
112N N channel transistor
113P p channel transistor
114N N channel transistor
115N N channel transistor
116 fuses
117 resistance
A1, A2, A3, A4 secondary cell
V0, V1, V2, V3, V4 voltage detecting terminal
R1, R2, R3 resistance